Glow-discharge-treated cellulose acetate (CA) membrane for a high linearity single-layer glucose electrode in the food industry

Abstract

The aim of this study was to develop a single-layer glucose enzyme electrode with extended linearity to be used in the food industry in order to determine the glucose content. An amperometric-based probe-type glucose enzyme electrode with Pt working electrode and Ag/AgCl reference electrode polarised at +650 mV was used. In this study, permselective behaviour of different polymeric membranes, which were prepared in our laboratory (cellulose acetate, polyurethane, polyetersulphone) and commercially available tract-etched polycarbonate, were investigated at different pH values (pH 4, 6, 7.4, 10) to estimate the magnitude of interferences caused by a group of different electroactive compounds. The selectivity tests showed that cellulose acetate membranes were the most convenient structure to establish a single-membrane recognition layer. The single surface of the cellulose acetate membranes was then modified with a plasma polymerisation technique at different glow-discharge parameters with amylamine monomer in order to show the effect of plasma polymerisation. The plasma-treated surface of the membranes was activated with glutaraldehyde then glucose oxidase (GOD) immobilised onto this site. The linearity and response time of these electrodes were investigated at pH 4 and 6. According to the results of linearity and response time tests, cellulose acetate membranes treated with amylamine at 5 W/20 min showed the best result. The linearity and response time of this electrode were found to be 320 mM glucose and 500 s, repectively at pH 4. Finally, the GOD electrode which was prepared with the most convenient membrane was used to determine the glucose content of some food stuff. Similar results were observed with the conventional measurement method.